[wix-users] Difference between svb6, scom and sreg arguments for heat

[Ven H]

In the WiX documentation given below, I am not able to completely
understand the difference between svb6, scom and sreg.

http://wixtoolset.org/documentation/manual/v3/overview/heat.html

I have a very large folder which has around 42K files and 3150 folder
amounting to 1.6GB content. This includes, dlls, COM components, images,
scripts, documents, style sheets, source files, html and so on. When I
execute heat command on this, it is taking around 1/2 hour to generate the
wxs file. I am executing with the following arguments.

heat dir MyFolder -cg MyCG -dr INSTALLDIR -gg -g1 -sfrag -srd -sw -*svb6*
-ke -var var.OutDir -out MyFolder.wxs

If I execute the below command on the same folder, the time taken is the
same.

heat dir MyFolder -cg MyCG -dr INSTALLDIR -gg -g1 -sfrag -srd -sw -*svb6
-scom* -ke -var var.OutDir -out MyFolder.wxs

But, if I execute the below command on the same folder, the time taken is
just 1 or 2 minutes.

heat dir MyFolder -cg MyCG -dr INSTALLDIR -gg -g1 -sfrag -srd -sw -*svb6
-scom*  *-sreg* -ke -var var.OutDir -out MyFolder.wxs

It looks like -sreg argument is making all the difference. So, I am not
sure what exactly is the impact of having / not having -sreg argument and
what is the difference between sreg and scom and svb6. If I add -sreg
argument, I am not sure if it can cause issues later on, since it deals
with registry.

But I can see a lot of difference in time taken. Can anyone please advise
on this?